This is an application for renewal of a training program in cellular and integrative neuroscience at the University of Maryland, Baltimore (UMB), School of Medicine. The goal of the program is to provide multi- disciplinary training to postdoctoral fellows based on the philosophy that neuroscientists require expertise in many facets of integrative neuroscience in order to participate effective in advanced investigations of the nervous system. Cell-cell communication is central to the integrative properties of the nervous system and plasticity of communication is increasingly recognized as a broad fundamental principle; indeed, plasticity of cell-cell communication is the organizing theme of the program. Six interactive interest groups, representing the research strengths of the program faculty, constitute focal points for investigation and training. These interest groups are: 1) neural systems, 2) cell-cell communication, 3) molecular aspects of cell-cell communication, 4) developmental neuroscience, 5) glia and 6) the application of optical methods in neuroscience. The program steering committee, an interdepartmental group of five senior investigators, is responsible for the administrative operation of the program including evaluating applicants and awarding stipends, monitoring trainee progress, coordinating recruitment efforts, and conducting an annual retreat. The steering committee and twelve additional established neuroscientists with long-standing track records of publications, successful postdoctoral training experience and extramural funding, constitute the primary faculty in whom rests the principal responsibility for supervision of trainees; several secondary faculty members collaborate with the primary faculty in research and training. In light of the explosive growth of outstanding neuroscience research at UMB, consistent success in competing for NIH funding and the large number of excellent postdoctoral fellows already trained by program faculty, this application requests support for eight fellows.